Alternative Sources of Energy: Definition, Types, Benefits & Limitations

Alternative Sources of Energy: We all know that energy can neither be created nor destroyed. We can only transform one form of energy into another. For example, the stored chemical energy of a cell is converted into light energy. The stored chemical energy of fossil fuels is converted into heat energy on burning them.

We all need energy for our daily activities. We obtain energy from natural resources like fossil fuels. Some of these natural resources are non-renewable and cannot replenish faster as we need them. The burning of fossil fuels causes many environmental issues like global warming and pollution. Nowadays, these resources are replaced by alternative sources of energy that replenish quickly and are eco-friendly. Let us learn more about alternative sources of energy in this article.

Alternative Sources of Energy Definition

Definition of Alternative Sources of Energy (Non-Conventional Sources of Energy): Alternative sources of energy are present in nature and can be replenished quickly. These are also known as non-conventional sources of energy. Alternative sources of energy do not use fossil fuels. They do not cause pollution and can be consumed over a long period without being exhausted.

Many renewable sources of energy come under the category of alternative sources or non-conventional sources of energy. For example, solar energy, wind energy, wave energy, and geothermal energy.

Types of Alternative Sources of Energy

The types of alternative sources of energy are explained below:

Wind Energy

The kinetic energy of high-speed winds is used to generate electricity by wind-powered generators. Windmills harness wind energy. A windmill consists of a tall pole on the top of which a fan-like structure is attached. This fan-like structure is called a wind turbine.

The force of high-speed winds makes the blades of the fan attached to the windmill rotate. The blades of the windmill are connected to the shaft of a generator, which also rotates with the movement of blades. This makes the generator produce electricity. A windmill is also used to lift water from a well. Wind energy is a renewable source of energy.

Hydroelectric Energy

In a hydroelectric power plant, the potential of stored water in a reservoir is converted into the kinetic energy of water. This kinetic energy of water is used to rotate the blades of the turbine connected to a generator. The rotating turbine drives the generator’s shaft, thereby converting the mechanical energy of the rotating shaft into electrical energy. It is also a renewable source of energy.

Solar Energy

Sun is the primary source of heat and light on the earth. The energy received by the earth from the sun is about \(1.4\) kilojoules per second per square meter, also known as the solar constant. Solar energy can be harnessed with the help of a solar cooker and solar cell. A solar cell is usually made of silicon that directly converts sunlight into electricity.

A typical solar cell produces a voltage of \(0.5\) to \(1\,\rm{V}\) and can produce about \(0.7\,\rm{W}\) of electricity. A solar panel consists of many solar cells. The electricity requirements of many households in remote areas are fulfilled by using solar panels. Street lights and traffic lights are also powered by solar energy. Solar cells are used in calculators.

A solar cooker is a device used to cook food. It consists of a box-like structure whose outer surface is painted black to absorb more heat, a thick sheet of glass to cover the food kept inside it, and a plane mirror reflector. The food to be heated is kept inside the box, and this box is kept in sunlight so that its reflector faces the sun. The mirror reflector reflects the sun rays to the glass sheet cover. The food absorbs the heat from the sun. Also, the thick glass sheet does not allow the loss of heat from the solar cooker to the surroundings.

Geothermal Energy

The heat energy of the earth’s interiors is known as geothermal energy. This energy is used to generate electricity. The trapped molten rocks in the region under the earth’s surface called hot spots heats the underground water. The steam produced by the hot water is allowed to rotate the blades of the turbines, which rotate the shafts of the generators connected to them.

Nuclear Energy

Nuclear energy is the most reliable source of energy. The fission of one uranium atom produces million times the energy produced by burning one atom of carbon from coal. Nuclear energy is produced by splitting the nucleus of a heavy atom into lighter nuclei. This process is called nuclear fission. It generates a large amount of energy that can be used to rotate generator turbines to produce electrical energy. In nuclear fission, the nucleus of uranium or plutonium is bombarded with low-energy neutrons.

Tidal Energy

Oceanic tides are the source of energy. Oceanic tides refer to the rise and fall of the water level of an ocean relative to coastal lines. Tides result from the gravitational force of the sun and moon on the earth. Energy can be harnessed from tides by constructing a dam across a delta. Turbines of generators are attached at the openings of these dams whose blades are rotated with the rise and fall in the ocean level, producing electricity.

Wave Energy

The kinetic energy of oceanic waves is used to produce electricity. These waves are caused by winds that blow across the sea. At a wave power station, chambers are constructed that trap seawater. These chambers have an opening at the top from which air is forced in and out when the water level rises or falls in the chamber. A generator turbine is fixed at these openings, which rotate with air movement, and the generator produces electricity.

Benefits of Using Alternative Sources of Energy

1. Alternative sources of energy do not use fossil fuels, so they do not produce greenhouse gas.
2. They are renewable. Therefore, they do not get exhausted by increasing their consumption.
3. The construction of dams for hydroelectricity helps in controlling floods.
4. The use of solar cookers and solar water heaters helps in saving fossil fuels.
5. They save money because once their power plants are set up, they only require maintenance.

Limitations of Renewable Sources of Energy

• 1. The initial installation of power plants is expensive. A large area of land is needed to set up wind energy farms (about \(2\) hectares area is required to set a wind energy farm for producing \(1\,\rm{MW}\) power). It can only be set up in areas where the minimum wind speed is about \(15\,{\rm{km}}/{\rm{h}}.\)
• 2. Many lands are submerged underwater while setting up a hydroelectric power plant and building a dam. It drastically affects aquatic life and wildlife. Methane gas is released when this submerged vegetation rots under anaerobic condition.
• 3. There are limited sites for setting up geothermal energy and tidal energy power plants.
• 4. Nuclear power plants produce radioactive wastes and radiation that can be a dangerous hazard if leaked accidentally.
• 5. The efficiency of renewable sources of energy like solar energy is low on a cloudy day.

Summary

From this article, we can conclude that alternative sources are the replacement of fossil fuels. They do not produce any pollution emissions and help in reducing global warming. Furthermore, these sources of energy are renewable because they are inexhaustible and cheap to operate and maintain.

FAQs on Alternative Sources of Energy

Q.1. What are the reliable alternative sources of energy?
Ans: Nuclear power, hydroelectric power, solar energy and wind energy are the most reliable sources of energy. 

Q.2. What do you mean by alternative sources of energy?
Ans: Alternative sources of energy are also known as non-conventional or renewable sources of energy. These sources of energy can never get exhausted and can be used endlessly. Alternative sources of energy reduce the undesirable effects of pollution caused by using fossil fuels.

Q.3. What are the disadvantages of alternative sources of energy?
Ans: Some of the disadvantages of alternative sources of energy are as follows:
1. There are only limited sites for setting up power plants of alternative sources of energy.
2. The initial cost of establishing the power plants of alternative sources of energy are expensive. 

Q.4. What are renewable sources of energy?
Ans: Sources of energy that are replenished faster than that at which they are consumed are called renewable sources of energy. They are inexhaustible energy sources—for example, wind, tide, hydropower and energy from the sun.

Q.5. What are the limitations of alternative sources of energy?
Ans: The initial installation of power plants of alternative sources of energy is expensive. There are limited sites for setting up their power plants.

Q.6. What are the benefits of using alternative sources of energy?
Ans: Alternative energy sources do not use fossil fuels, so they do not produce greenhouse gas. Alternative sources of energy are renewable. Therefore, they do not get exhausted by increasing their consumption. 

Q.7. What are some examples of alternative sources of energy?
Ans: Tidal energy, wave energy, geothermal energy, solar energy, hydroelectric energy, nuclear energy, wind energy are some examples of alternative sources of energy.

Q.8. Are renewable and alternative sources of energy all the same?
Ans: Yes, alternative energy sources and renewable energy sources are the same because these energy sources do not include fossil fuels and can be replenished faster on demand.